Cephalosporins having a ureido substituted acyl sidechain and various groups in the 3-position are disclosed by Erickson in U.S. Pat. No. 3,673,183, Welch et al. in U.S. Pat. No. 3,708,479, Dolfini in U.S. Pat. No. 3,833,568, Breuer in U.S. Pat. No. 3,860,591, and Breuer et al. in U.S. Pat. Nos. 3,996,217, 3,996,218, 4,024,135, 4,088,815, 4,088,816, and 4,127,716.
Various 7.alpha.-methoxy cephalosporins having a ureido substituted acyl sidechain and various groups in the 3-position are disclosed by Dolfini in U.S. Pat. Nos. 3,978,051, 3,989,693, 3,989,697, 4,000,134 and 4,061,852.
Ochiai et al. in U.S. Pat. No. 4,098,888 disclose cephalosporins having an aminothiazolyl acetamido acyl sidechain with an amino, hydroxy, or imino group on the .alpha.-carbon atom of the acyl sidechain.
Heymes in U.S. Pat. No. 4,152,432 disclose cephalosporins having an aminothiazolyl acetamido acyl sidechain with an imino group on the .alpha.-carbon atom of the acyl sidechain.
Hoechst in German Offenlegungsschrift No. 2,716,677 discloses .alpha.- and .beta.-sulfoxides of cephalosporins having an aminothiazolyl acetamido acyl sidechain with an imino group on the .alpha.-carbon atom of the acyl sidechain.
Marx et al. in U.S. Pat. No. 4,075,337 disclose the preparation of antibacterially active cephalosporin sulfoxides.
Cook et al. in U.S. Pat. Nos. 3,971,778 and 4,138,555 disclose the preparation of additional antibacterially active cephalosporin sulfoxides.